^timtitii 



FOR GENERAL READERS. 



Vol. II. 



FRIDAY, AUGUST 31st, 1888. 



No. 9. 



PAGE 



Scientific Table Talk 193 



Ice-Making Machine {illus.) .. ... 194 



Geology of Bath.— I. (illus.) 195 



General Notes 199 



Experimental Physics {illus.) ... 201 

 Automatic Constant-Level Balance 



{illus.) 201 



Odours, and their Functions 201 



Natural History : 



Sing-Sing Antelope {illus.) 203 



A Luminous Coleopterous Larva from 



Brazil 204 



The Food of the Sparrow ... ... 204 



Miscellaneous Notes 204 



CONTENTS. 



PAGE 



The Botany of Bristol— II. 205 



New Process of Sugar Refining ... 206 



Reviews : 



Bees and Bee-Keeping ... ... 207 



Roman Bath. — II 208 



Meeting of German Natural Philo- 

 sophers and Physicians at Cologne 209 



Abstracts of Papers, Lectures, etc. : 



Iron and Steel Institute — ... 210 



Halifax Scientific Association ... 213 

 Thirsk and District Naturalists' 



Society ... ... ... ... 213 



Middlesex Natural History Society 213 



Leeds Naturalists' Club and Scien- 

 tific Association ... 

 Falmouth Naturalist Society 

 Correspondence : 



Ballooning — Prescription for Mos- 

 quitoes — Petals of the White Jas- 

 mine 

 Answers to Correspondents ... _ 

 Announcements 

 Recent Inventions 

 Sales and Exchanges ... 



Selected Books... 



Notices 



Meteorological Returns 



213 

 213 



214 

 214 

 214 

 215 

 216 

 216 

 216 

 216 



SCIENTIFIC TABLE TALK. 



By W. Mattieu Williams, F.R.A.S., F.C.S. 



I am glad to see that the subject of glaciation was taken 

 up in Scientific News of August 10th for two reasons — 

 first, because the work done by glaciers in determining 

 the distribution of the materials and the configuration of 

 the present surface of the globe is so great ; and, secondly, 

 because the phenomena are on the surface within reach 

 of all, thus affording opportunities of direct study to any- 

 body and everybody, with a minimum of technical pre- 

 paration. Other departments of geology demand a 

 knowledge of mineralogy and palaeontology, besides sec- 

 tions and appliances. Once acquainted with the charac- 

 teristic vestiges of glaciation, they may be broadly 

 observed from the windows of an express railway train 

 or the deck of a coasting steam-packet, and a collection 

 of their most interesting details may be made by carry- 

 ing no other appliances than a few sheets of paper and a 

 piece of shoemakers' heel-ball. 



In England, north of Finchley, in all parts of Scotland 

 and Ireland, and throughout middle and northern Europe 

 and America, vestiges of ancient glaciers abound. 



I had the good fortune to be started early in the prac- 

 tical study of the subject by attending the natural history 

 course of Professor Jamieson in the University of Edin- 

 burgh in 1 841. 



He was then a very old man, the last of the Wernerian 

 ■school, and very conservative ; nevertheless he took up 

 this subject with exceptional enthusiasm, although it was 

 then an innovation. In the following summer I spent a 

 day with Agassiz in his " Hotel des Neufchatelois," a 

 wooden shed built on a great boulder that was floating 

 on the Aar glacier. Here he spent his summer holidays 

 in company with a jovial band of students, and collected 

 .the greater part of the material of his classic treatise, 

 " Etudes sur les Glaciers," which was published at Neuf- 

 chatel in 1840, and supplied Jamieson with the material 

 of his lectures in 1841. 



In order to obtain sound ideas concerning glaciation, 

 we must first understand clearly what a glacier really is. 

 It is not sufficient to know that it is " a sea of ice ; " we 

 must understand the difference between a true glacier 



and a mere accumulation of compressed snow, and the con- 

 ditions upon which the formation of true glaciers depend. 



We know what becomes of the redundant rain which 

 falls on the tops and sides of hill and mountains that do 

 not reach the snow line. It runs down their slopes in 

 rills and torrents, forming a river in the valley below, 

 which gathers as it flows more and more of such contri- 

 butions, and finally pours them all into the sea. Broadly 

 speaking, every valley is, at its lowest part, the bed of a 

 river, or of a lake which is simply an outspread river. 



But when we rise above the snow-line we come upon 

 a region of solid precipitation, where the water that falls 

 from the clouds is solid crystallised water, is snow ; the 

 height of the snow-line being that at which the annual 

 thawing work just balances the total snow-fall of the 

 year. Above this the total snow-fall of each year exceeds 

 each year's thawing. Therefore, above this, there must 

 be continual accumulation. 



What becomes of such accumulation ? 



A full reply to this question tells the whole story of 

 the origin, distribution, and movement of glaciers, as 

 well as of icebergs and avalanches. I will only attempt 

 a reply in condensed summary. 



It is evident that if we had a mountain shaped as a 

 symmetrical cone, with its apex far above the snow-line, 

 the accumulation of snow would be piled up until the 

 slope of its sides exceeded that of the angle of repose for 

 such material, and then it would slide down in the form 

 of avalanches. 



The same would occur on a long symmetrical un- 

 broken ridge of mountain. But such unbroken symmetry, 

 even if it existed at first, would be destroyed by these 

 avalanches. They would furrow the slopes in the course 

 of their downsliding. 



As a matter of existing fact all ordinary mountains are 

 thus furrowed, and usually very deeply. It is evident 

 that such furrows must determine the course of overflow 

 of the accumulating snow. It is also a matter of existing 

 fact that all such furrows or steep lateral valleys running 

 downwards from great super-snow-line regions or neve 

 (as the}' are named in Switzerland) are either the beds 

 of glaciers, or dangerous regions visited occasionally by 

 avalanches and avoided accordingly. 



